Gastrointestinal Device

ABSTRACT

A gastrointestinal device and method for retrieving the device are disclosed. The device may include a stent including a plurality of strands forming first and second ends, the strands configured to move between a retrieval configuration, with substantially parallel strands, and a deployed configuration, wherein the strands form proximal and distal portions having first and second diameters larger than the pyloric sphincter. The device may include a connector assembly including proximal, middle, and distal connectors. The middle connector may be coupled to the proximal and distal connectors when the strands are in the deployed configuration. The strands may be attached to the proximal and distal connectors and the first and second ends. The device may include a release mechanism configured to decouple the proximal connector from the middle connector. Decoupling of the proximal and middle connectors may allow the strands to move from the deployed to retrieval configuration.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/700,841, filed Apr. 30, 2015, which claims the benefit of U.S.provisional application Ser. No. 61/986,814 filed Apr. 30, 2014, thedisclosures of which are hereby incorporated in their entirety byreference herein.

TECHNICAL FIELD

The present disclosure relates to a gastrointestinal device, forexample, to assist in weight loss.

BACKGROUND

Obesity (e.g., a body mass index (BMI)>30) is an epidemic in the UnitedStates and around the world, where an estimated greater than one-thirdof U.S. adults and over a billion people worldwide are obese.Obesity-related conditions, including heart disease, stroke, type 2diabetes and certain types of cancer, are some of the leading causes ofpreventable death. The estimated annual medical cost of obesity in theU.S. was $147 billion in 2008 U.S. dollars; the medical costs for peoplewho are obese were $1,429 higher than those of normal weight. Greaterthan 400,000 deaths in the United States each year are attributed toobesity.

Diet and exercise programs are effective in promoting weight loss,however, it is estimated that less than 5% of those who engage in suchprograms are able to sustain them long term. Surgical weight losssurgery is very effective, however, it is associated with morbidity andmortality rates between 0.1 and 2%. Weight loss surgery is typicallyreserved for the morbidly obese (e.g., a BMI>40), which accounts forless than 5% of the obese population. One example of an effective weightloss surgery is a Roux en Y gastric bypass, which is estimated to costover $35,000 and includes up to three days of hospitalization.

SUMMARY

In at least one embodiment, a gastrointestinal device for reducing flowthrough a pyloric sphincter of a patient is provided. The device mayinclude a stent including a plurality of strands forming first andseconds ends, the plurality of strands configured to move between aretrieval configuration, wherein the plurality of strands aresubstantially parallel, and a deployed configuration, wherein theplurality of strands form a proximal portion having a first diameter anda distal portion having a second diameter. The first and seconddiameters may be larger than a diameter of the pyloric sphincter. Thedevice may include a connector assembly including a proximal connector,a middle connector, and a distal connector. The middle connector may becoupled to the proximal connector and the distal connector when theplurality of strands are in the deployed configuration. The plurality ofstrands may be attached at the first end to the proximal connector andat the second end to the distal connector. The device may furtherinclude a release mechanism attached to the proximal connector andconfigured to decouple the proximal connector from the middle connector.Decoupling of the proximal and middle connectors may allow the pluralityof strands to move from the deployed configuration to the retrievalconfiguration.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cut-away view of a deployed gastrointestinaldevice, according to an embodiment;

FIG. 2 is cross-section of a deployed gastrointestinal device, accordingto an embodiment;

FIG. 3 is an exploded view of a gastrointestinal device, according to anembodiment;

FIG. 4 is front perspective view of a deployed gastrointestinal device,according to an embodiment;

FIG. 5 is a rear perspective view of a deployed gastrointestinal device,according to an embodiment;

FIG. 6A is a perspective view of a gastrointestinal device in anunlocked configuration, according to an embodiment;

FIG. 6B is a cross-section of the device of FIG. 6A, according to anembodiment;

FIG. 7 is a perspective view of the device of FIG. 6A with a sleevesurrounding the stent, according to an embodiment;

FIG. 8 is a cross-section of a gastrointestinal device in an insertionconfiguration, according to an embodiment;

FIG. 9 is a schematic cut-away view of a gastrointestinal device in aninsertion configuration, according to an embodiment;

FIG. 10A is a perspective view of a connector assembly in an unlockedconfiguration, according to an embodiment;

FIG. 10B is a cross-section of the connector assembly of FIG. 10A.

FIG. 11A is the connector assembly of FIG. 10 in a locked configuration;and

FIG. 11B is a cross-section of the connector assembly of FIG. 11A.

DETAILED DESCRIPTION

As required, detailed embodiments of the present invention are disclosedherein; however, it is to be understood that the disclosed embodimentsare merely exemplary of the invention that may be embodied in variousand alternative forms. The figures are not necessarily to scale; somefeatures may be exaggerated or minimized to show details of particularcomponents. Therefore, specific structural and functional detailsdisclosed herein are not to be interpreted as limiting, but merely as arepresentative basis for teaching one skilled in the art to variouslyemploy the present invention.

As described in the Background, weight loss procedures are currentlylimited to surgical operations which may be costly, relatively risky,and may require extended hospitalization. In addition, surgery maypermanently alter the bowel anatomy and can lead to permanent changes inbowel function including increased rates of abdominal pain and diarrhea.The Roux en Y gastric bypass is a highly invasive, permanent procedure.The procedure generally involves creating a 15-30 ml gastric pouch. Thejejunum is divided and is anastomosed (connected) to the gastric pouch.A significant, but infrequent, early complication is a leak at theanastomotic or staple line. Leaks from the anastomosis have lowfrequency (0.4% to 5.2%) but have devastating consequences, with up to a50% mortality rate. Postoperative hemorrhage is a more frequent event,cited in the literature as occurring between 1.9% to 4.4%. Small bowlobstruction is related to internal hernias and range from an incidenceof 1% to 9%. Finally, a late complication may arise formGastrojejunostamy anastomic stricture with incidence rates reported from2.9% to 23% and appears to be more prevalent with laparoscopicprocedures rather than open surgery. These relatively high rates ofcomplications are directly related to the invasiveness of the surgery.

A byproduct of gastric bypass surgery is a significant reduction in type2 diabetes. A team of researchers at Group Health Research Institutestudied 4,434 diabetic patients for fourteen years from 1995 to 2008.All patients were obese enough to be candidates for bypass surgery. Twothirds of the study's patients had remission of diabetes after gastricsurgery. However one third re-developed diabetes within five years ofgastric surgery. The study suggests that after gastric surgery, diabetesmay stay away longer in those people whose diabetes was less severe andat an earlier stage at the time of surgery.

Several devices are in development that attempt to provide non-surgicalweight-loss alternatives. One device tries to mimic the Roux en Y bypassby placing a “sleeve” of PTFE through the duodenum and proximal jejunumto prevent absorption of gastric contents. In preliminary trials, thedevice appears to be effective in promoting weight loss and improvingglycemic control in morbidly obese diabetics. Pilot studies showed thedevice improved serum glucose concentrations and HbA1c levels andreduced body weight.

However, there are some significant complications related to removal ofthe duodenal sleeve device. Complications may include device migration,device obstructions, abdominal pain, ulceration, perforation, and hepticabscesses. Fifteen of thirty nine implanted devices (38%) were removedbefore the end of one study. A similar percentage were removed inanother study primarily due to migration, GI bleeding, and abdominalpain. The device is anchored to the first portion of the small bowel(the duodenal bulb) using metal barbs. Anchoring to this portion of thebowel increases the risk of dislodgement where the sleeve can detach andfloat down the intestine. The migrated sleeves can block the intestinaltract and may require surgery to remove. The device is meant to beremoved after several months. However, removing the device is quitedifficult as the metal barbs anchoring the device to the duodenum mustbe forcefully pulled out, which can increase the risk of complications,such as bleeding and perforation of the bowel.

Enrollments in the clinical study for the device were ended due to fourcases of 325 implants resulting in hepatic abscesses. The anchoringsystem of the device has barbs that dig into the duodenum and may havecaused infection and affected the liver. The hepatic abscess risk islikely related to the wire-induced ulceration within the duodenal bulbwith either or both secondary bacterial seeding and perforation, eitherovert or microscopic. The construction of the anchoring mechanism isinvasive, similar to the design of barbed wire, with a fixed diameterring of barbed wire expanded within the proximal duodenal bulb. Duringthe dwell time of the device (up to 12 months) there is localized tissueinteraction by the direct expansion of the barbed ring and thecontractile activity of the bulb, including superimposed MMC expulsivesweep contractions, creating potential risk issues for not onlyinfection, but symptomatic ulceration and gross clinical perforationsecondary to ulceration.

Another device, meant to improve on the anchoring technique of the abovedevice, utilizes a stent straddling the pyloric sphincter to anchor thesleeve into the stomach. This avoids the complications associated withbarbed elements described previously. This device includes a couplingmechanism to release the sleeve which provides the therapy. This wouldallow the removal of the therapeutic sleeve, but not of the stentlocking mechanism. The device may also be susceptible to migration.

A different type of device that has been developed in an attempt to cureobesity is implanted intragastric balloons (IGB), designed to fill spacein the stomach. One such IGB has been implanted over 200,000 timesinternationally. A study has been completed that demonstrates that theballoon causes effective weight loss over the 9 months requested by theFDA, as measured either by % EWL (excess weight loss) or TBW (total bodyweight). The data also demonstrates a “legacy effect” which extendsbeyond 12 months during which patients continue to maintain weight lossafter removal of the balloon at 6 months. A recent meta-analysis wasperformed on published experiences involving approximately 8,500 IGBpatients showed that the device supports effective weight loss during 6month use and a good safety profile. IGB cycling extended over longperiods of time (years) in morbidly obese patients has also demonstratedweight loss which rivals that achieved by gastric bypass surgery. OneIGB device is a silicone polymer device with performance characteristicsat the present time which dictate safe use (low risk for collapse)during a 6 month dwell time. Another device is a dual IGB system made ofa polymer with different response characteristics to gastric secretionsover time. This balloon offers similar, but not better, weight lossresults over 6 month use. Removal of this device is more complex thanthe single IGB and may ultimately be a deterrent over the use of asingle balloon IGB, given similar weight loss outcomes. Both balloonsinduce weight loss by reducing capacity, inducing satiety, and delayinggastric emptying (only during the dwell period). There have been noformal studies documenting the physiology and mechanics of tolerance toan indwelling IGB with subsequent weight gain. It is speculated thatthis is due primarily to gastric distention and tolerance of greatervolume.

Results from two randomized clinical trials of another IGB device weremixed. In one study with 43 patients, there was no difference betweenthe twenty balloon patients and the twenty three receiving a placebo. Inthe second study with thirty two patients, the balloon patients hadsignificantly greater decreases in BMI.

In addition to potentially unacceptable weight loss results, if a singleballoon ruptures, the deflated balloon may migrate into the intestinesand require surgical treatment. A dual balloon system is more robust byadding a second redundant balloon. If one balloon deflates, the secondwill continue to block migration until the device is removed. However,this dual balloon system is harder to fill and remove than the singleballoon system. Patients may overcome the benefits of the space taken upby the balloon by continuing to overeat. This will distend the stomachand potentially obviate the advantage of the implant.

The disclosed gastrointestinal device addresses one or more of thedisadvantages of the above devices by providing a safe, easily removabledevice with improved weight loss performance. The disclosed device mayprovide two mechanisms of weight loss, including a reduction inabsorption gastric contents in duodenum and proximal jejunum and theslowing of gastric emptying to prolong/increase satiety. The device mayalso treat type 2 diabetes in both obese and non-obese patients. Thedevice may be easily and safely deployed, either endoscopically orradiologically. A device which can be implanted by multiple physicianspecialties (e.g., endoscopically or radiologically) may broaden thepotential base of users who can implant the device using eithertechnique. When the desired amount of weight loss has been achieved, thedevice may be easily and atraumatically removed.

With reference to FIGS. 1-11, a device 10 is shown. The device 10 willbe described herein as a gastrointestinal device 10, however, the device10 may be used for any application in which a reduction in flow isdesired between two regions of the body. As shown in FIG. 1, when usedas a gastrointestinal device, the device 10 may be configured tostraddle the pylorus 101 or pyloric sphincter 102, which connects thestomach 103 to the duodenum 104 (the first portion of the smallintestine).

The device 10 may include a stent 12 and a connector assembly 14. Thestent 12 may include a plurality of strands or wires 16. The strands 16may be formed of any suitable material, such as a metal or polymer. Inat least one embodiment, the strands 16 are formed of a shape-memory orheat-formable material. The strands 16 may also be formed of a highlyelastic material, for example, a material that exhibits superelasticity.In one embodiment, the strands 16 may be formed from a nickel-titaniumalloy, also known as nitinol. The strands 16 may be woven or braidedtogether or they may be un-woven, separate strands 16.

In at least one embodiment, the strands 16 of the stent 12 may be formedinto a first or proximal portion 18 and a second or distal portion 20.The first and second portions may have an enlarged diameter relative tothe rest of the stent 12. The first portion 18 may be configured to belocated proximal to the pylorus 101 within the stomach and the enlargeddiameter may be configured to be larger than a maximum diameter of thepylorus to prevent distal movement of the stent 12. The second portion20 may be configured to be located distal to the pylorus 101 within theduodenum and the enlarged diameter may be configured to be larger than amaximum diameter of the pylorus to prevent proximal movement of thestent 12. Together, therefore, the first and second portions maystraddle the pylorus 101 and prevent the device from migratingproximally or distally past the pylorus.

The first and second portions may be disc or pancake shaped, such thatthey taper from a reduced diameter 22 to a maximum diameter 24 and backto a reduced diameter 22. The first and second portions may each defineproximal and distal opposing surfaces 26 and 28. For example, the firstportion 18 may form a proximal surface or face and an opposing distalsurface or face, and the second portion 20 may form the same.Accordingly, the proximal surface 26 of the first portion 18 may facethe stomach and the distal surface 28 of the first portion 18 may facethe antral side of the pylorus, while the proximal surface 26 of thesecond portion 20 may face the distal side of the pylorus and the distalsurface 28 of the first portion 18 may face the duodenal bulb.

The diameter of the first and second portions may continuously increasefrom one side to the maximum diameter 24 and then continuously decreasefrom the maximum to a reduced diameter 22 on the other side. The firstor proximal portion 18 of the stent 12 may have a larger diameter (e.g.,maximum diameter) than the second or distal portion of the stent 12.Since partially digested food (e.g., chyme) flows from the stomach intothe small intestine, there will be a greater force or pressure on thedevice in the proximal to distal direction. Therefore, the first portion18 may have a larger diameter in order to more effectively resist thepressure from the flow of partially digested food. In contrast, thereare less forces or pressures acting in the distal to proximal directionon the second portion 20. For example, stomach churning (segmentation)occurs in the small intestine through muscular constriction of theintestinal wall. This process forces food backward and forward and mayimpose retrograde force on the device. Accordingly, the second portion20 may have a smaller diameter since the risk of proximal migration isnot as great. Furthermore, reducing the diameter of the second portion20 relative to the first portion 18 may reduce the area of interactionbetween the device and the duodenum. This reduced diameter will reducethe risk for irritation of the duodenal tissue lining and avoid adverseeffects such as ulceration and bleeding. The second portion 20 having asmaller diameter may also assist in insertion of the device by allowingit to pass through the pylorus more easily.

The first and second portions may both have a diameter (e.g., maximumdiameter) that is larger than a diameter of the fully opened pylorus. Inone embodiment, the first portion 18 may have a diameter, such as amaximum diameter, that is from 15 to 45 mm, or any sub-range therein.For example, the first portion 18 may have a diameter of 20 to 40 mm, 25to 35 mm, or about 30 mm (e.g., ±5 mm). The first portion 18 may have alarger diameter than the second portion 20 (e.g., max diameters). In oneembodiment, the second portion 20 may have a diameter, such as a maximumdiameter, that is from 15 to 40 mm, or any sub-range therein. Forexample, the second portion 20 may have a diameter of 15 to 35 mm, 20 to30 mm, or about 25 mm (e.g., ±5 mm). The difference between the firstand second portion 20 diameters may be defined as a ratio. In oneembodiment, a ratio of the diameter (e.g., max diameter) of the seconddiameter to the first diameter is less than 1:1. For example, the ratiomay be less than 0.9:1, 0.8:1, 0.7:1, 0.6:1, or 0.5:1. In oneembodiment, the ratio may be from 0.6:1 to 0.9:1. In another embodiment,the ratio may be from 0.7:1 to 0.9:1. In another embodiment, the ratiomay be from 0.8:1 to 0.9:1. In another embodiment, the ratio may be from0.75:1 to 0.85:1.

The plurality of strands 16 in the stent 12 may have a first, proximalend 30 and a second, distal end 32. The first and second ends of thestent 12 may be connected, attached, or otherwise coupled to theconnector assembly 14. The connector assembly 14 may include two or moreconnectors or parts, including a proximal connector 34 and a distalconnector 36. The proximal connector 34 may be spaced apart andconfigured to receive, couple, or attach to the first end 30 of theplurality of strands 16. The first end 30 of the strands 16 may extendin a proximal or antegrade direction from the first portion 18 of thestent 12 to couple to the proximal connector 34. The proximal connector34 may therefore be proximal to the first portion 18 of the stent 12when the device is in the deployed position and may reside in thestomach of the patient. The distal connector 36 may be configured toreceive, couple, or attach to the second end 32 of the plurality ofstrands 16. The second end 32 of the strands 16 may extend in a distalor retrograde direction from the second portion 20 of the stent 12 tocouple to the distal connector 36. The distal connector 36 may thereforebe distal to the second portion 20 of the stent 12 when the device is inthe deployed position and may reside in the duodenum of the patient.

The proximal and distal connectors may each have a plurality of openingsor apertures 38 defined therein. The openings 38 may be spaced around aperimeter of the connectors in a generally annular pattern. The openings38 may be configured to receive the strands 16 of the stent 12 andsecure the strands 16 to the connector. For example, the openings 38 inthe proximal connector 34 may receive and secure the first end 30 of thestrands 16 and the distal connector 36 may receive and secure the secondend 32 of the strands 16. The number of openings 38 in each connectormay match or correspond to the number of strands 16 in the stent 12,although this is not required (e.g., there may be more or lessopenings). The strands 16 may be secured within the openings 38 in anysuitable manner. For example, an adhesive may be applied to secure thestrands 16, the strands 16 may be crimped or otherwise mechanicallyfastened within the openings 38, or the strands 16 may be welded (e.g.,conventionally or ultrasonically) within the openings.

The connectors may have a generally circular cross section transverse totheir longitudinal axes. The proximal and distal connectors may eachhave central channel or lumen 40 defined therein, which may beconfigured to allow chyme to flow through the device, as well asfacilitate insertion and/or removal of the device. The proximal anddistal connectors may each have a width or diameter that is less thanthe maximum diameters of the first and second portions of the stent 12.Accordingly, the stent 12 may have a reduced diameter portion 22 in theregion where the first and second ends of the strands 16 attach to theproximal and distal connectors. In one embodiment, the stent 12 diametermay be at its minimum in the region where it attaches to the proximaland/or distal connector. The diameter of the stent 12 in the regionwhere it attaches to the proximal and/or distal connector may be thesame or similar to the diameter of the stent 12 in a region between thefirst and second portions. This region may be referred to as the valleybetween the first and second portions and may be the portion that islocated within the pylorus when the device is deployed.

The connector assembly 14 may also include a middle connector 42 ormiddle portion 42. The middle connector 42 may extend at least partiallybetween the proximal and distal connectors. In one embodiment, themiddle connector 42 is not connected or attached to the stent 12. In thedeployed configuration, the middle connector 42 may be locatedcompletely within the strands 16 of the stent 12 or surrounded by thestrands 16. The middle connector 42 may be coupled at its proximal endto the proximal connector 34. The middle and proximal connectors may becoupled in any suitable manner. In one embodiment, the middle andproximal connectors are coupled via a threaded engagement 44. As shownin FIGS. 2, 3, 8, 10, and 11, the middle connector 42 may include malethreads 46 that are configured to engage female threads 48 defined inthe proximal connector 34. However, the threading may also be reversed,such that the middle connector 42 includes female threads and theproximal connector 34 includes male threads.

In at least one embodiment, the threaded engagement between the middleand proximal connectors is relatively coarse, or has a large pitch(e.g., fewer threads per axial distance). The threaded engagement may bea single start thread or a multiple start thread (e.g., two start orthree start). In one embodiment, the male threads (e.g., on the middleconnector 42) may have a pitch of 2 to 8 mm, or any sub-range therein.For example, the pitch may be from 3 to 7 mm, 3.5 to 6 mm, or about 4.2mm (e.g., ±0.5 mm). The thread may have any suitable diameter, such as0.25 to 0.5 inches or about 0.375 inches (e.g., ±0.1 inch). A largepitch, and therefore a large angle of repose, may allow the middle andproximal connectors to disengage or decouple more easily than a smallpitch. The angle of repose may also be referred to as the angle offriction, and generally refers to the maximum angle at which a load canrest motionless on an inclined plane due to friction, without slidingdown. In one embodiment, the angle of repose of the threaded engagementmay be from 3 to 15 degrees, or any sub-range therein, such as 4 to 12degrees, 5 to 10 degrees, or about 8 degrees (e.g., ±2 degrees).Additional properties that may affect the disengagement of the threadsmay include the lubricity and the smoothness of the connectors. In oneembodiment, all of the connectors in the connector assembly 14 may beformed of a plastic, such as ABS, nylon, acetyl, Teflon, PP, or PE.Plastics generally have a high lubricity with each other and may allowthe threads to disengage. In another embodiment, one or more of theconnectors may be formed of metal, such as stainless steel. For example,the middle connector 42 may be partially or fully formed of a metal andthe proximal and distal connectors may be formed of plastic. Metals andplastics generally have a high lubricity with each other and may allowthe threads to disengage.

In order to prevent relative movement or unthreading between the middleand proximal connectors when the device is deployed, a release mechanism50 may be provided to control the disengagement of the connectors. Therelease mechanism 50 may be configured to prevent relative movement ofthe connectors until the release mechanism 50 is activated or actuated.The release mechanism 50 may be any device capable of switching betweena locked or unactuated position, in which the threads and prevented fromdisengaging, and an unlocked or actuated position, in which the threadsare free to disengage. In one embodiment, the release mechanism 50 mayinclude a pin or rod 52. The proximal and middle connectors may eachinclude a groove or channel 54 that extends through their threads. Whenthe connectors are threadedly engaged, the channels 54 may cooperate toform a passage 56 that is configured and sized to receive the pin 52.Accordingly, when the pin 52 is inserted into the passage 56, thethreads of the proximal and middle connectors are locked together andcannot be unscrewed. When the pin 52 is not inserted in the passage 56,the threads are able to be unscrewed. The pitch of the threads may beconfigured to allow the proximal and middle connectors to be unscrewedwith relatively little force being applied when the pin 52 is notinserted.

The middle connector 42 may include at least one projection 58 extendingfrom its proximal end 60 toward its distal end 62. There may be two,three, four, or more projections, for example, 2 to 10, 2 to 8, 2 to 6,or 2 to 4 projections. The projections may be radially spaced to form achannel or passage 64 extending from the proximal connector 34 towardsthe distal connector 36. Each projection 58 may include a snap fitelement or barb 66, which may be located at a distal tip 68 of theprojection. The snap fit elements may include a stop 70 extendingperpendicular or substantially perpendicular to the long-axis of theprojection 58 and radially outward. The snap fit elements may alsoinclude a ramp 72 extending at an angle from the stop 70 to a tip of theprojection. The projections 58 may be formed of a resilient materialthat can deform or deflect from its original position and return to itsoriginal position.

The snap fit elements of the middle connector 42 may be configured toengage a flange or lip 74 of the distal connector 36 when the device isin the deployed position. The flange or lip 74 may be annular or extendaround a perimeter of the distal connector 36. The flange or lip 74 mayalso be continuous around the perimeter or may have gaps orinterruptions. The stops 70 of the snap fit elements may engage theflange or lip 74 when the device is in the deployed position and preventthe distal and middle connectors from being pulled away from each other.Accordingly, when the device is in the deployed position, the proximal,middle, and distal connectors may be coupled together such that theproximal and distal connectors cannot move axially apart or away fromeach other. The proximal and middle connectors may be coupled by athreaded engagement and the middle and distal connectors may be coupledby snap fit elements of the middle connector 42 engaged with a flange onthe distal connector 36.

The distal connector 36 may include a threaded portion 76 to facilitateinsertion, movement, or alteration of the device. The threaded portion76 may include male or female threading. The threaded portion 76 may beintegral to the distal connector 36 or it may be a separate componentthat is attached or coupled to the distal connector 36 (e.g., byadhesive or welding). The channel or lumen of distal connector 36 mayextend through the threaded portion 76 such that partially digested foodpasses through the threaded portion 76 when the device is deployed.

The device may further include a sleeve 78 configured to extend into theduodenum and, in some embodiments, into the proximal jejunum. The sleeve78 may be formed of a biocompatible polymer and may be impermeable orsemi-permeable with respect to partially digested food and stomachfluids that are passed from the stomach to the small intestine. Thesleeve 78 may be hollow, such that a lumen or passage is formed from aproximal end of the sleeve connected to the device to a distal end ofthe sleeve. The proximal end 80 of the sleeve may be attached to thedistal connector 36. The attachment may be rigid or fixed, such thatremoval of the device requires removal of the sleeve, and vice versa.For example, the sleeve may attached by adhesive (e.g., glue) or weldedto the distal connector 36. The sleeve may connect to the distalconnector 36 such that it surrounds an exit of the lumen in the distalconnector 36. The sleeve may be dip or blow molded from one of severalpolymers, such as PTFE (Teflon), polyurethane or silicone.

Accordingly, partially digested food may travel from the stomach,through the lumens of the proximal connector 34 and the distal connector36, through the sleeve, and exit in a distal portion of the duodenum orin the jejunum. The sleeve therefore is configured to reduce oreliminate the absorption of nutrients in the duodenum and proximaljejunum (depending on sleeve length), thereby reducing the number ofcalories absorbed by the patient.

Since the device may be deployed over a relatively long time period, itmay be important to minimize or prevent tissue in-growth into the stent12. Tissue in-growth may inhibit removal of the device and may causeremoval to be traumatic to the tissue in and around the pylorus. In atleast one embodiment, the spaces between the strands 16 in the stent 12may be blocked or filled to prevent tissue in-growth. In one embodiment,the stent 12 may be partially or completely surrounded by a sheath 82.The sheath 82 may be formed of a polymeric material, such as anelastomer (e.g., silicone). The sheath 82 may surround at least thefirst and second portions of the stent 12, and may cover all externallyexposed strands 16. By covering the strands 16 of the stent 12, tissuein-growth may be prevented and the device may remain detached from thestomach, pylorus, and duodenum of the patient. The sheath 82 may beflexible and elastic enough that it conforms to the outer shape of thestent 12 in both the deployed and collapsed configurations (explained inmore detail below).

In another embodiment, the strands 16 of the stent 12 may be partiallyor completely embedded within a polymeric material, such as an elastomer(e.g., silicone). In this embodiment, the strands 16 are not covered onone side or surface, but encapsulated by the polymeric material suchthat the strands 16 are not exposed to the environment/surroundings atall. Embedding the strands 16, or at least a portion of the strands 16,in a polymeric material may minimize or prevent tissue in-growth, asdescribed above, as well as provide additional resistance to corrosion.While an outer sheath may protect the strands 16 from exterior corrosivesubstances, the strands 16 may still be exposed on an interior of thestent 12. Embedded strands 16 may be isolated from corrosive substances,such as stomach acids, both external and internal to the stent 12. Inone embodiment, the strands 16 may be embedded in the polymeric material(e.g., silicone) by inflating a balloon inside the stent 12 and dippingthe stent 12 in liquid silicone. However, any suitable method ofembedding the strands 16 in the polymeric material may be used. Thepolymeric material may be flexible and elastic enough that it conformsto the shape of the stent 12 in both the deployed and collapsedconfigurations (explained in more detail below).

When the device is deployed across the pylorus of a patient, a lumen orchannel 84 may be formed from the stomach, through the proximal, middle,and distal connectors (the connector assembly 14), and into the sleeve(or into the duodenum if there is no sleeve). Partially digested food(e.g., chyme) may therefore travel through the lumen 84 in the device ina manner similar to the pylorus (e.g., without the device). It has beendiscovered, however, that reducing the flow of chyme from the stomachinto the intestines, and thereby slowing the rate of gastric (stomach)emptying, may result in weight loss in a patient. By increasing the timefor the stomach to empty, the patient feels full, or satiated, forlonger. This prolonged feeling of fullness reduced the desire to eat,which may result in less calories being consumed.

In at least one embodiment, the lumen 84 of the connector assembly 14may be sized and configured to reduce the flow of partially digestedfood from the stomach to the small intestine. The lumen 84 may have adiameter that is smaller than a diameter of the pylorus, therebyincreasing the resistance to the flow of chyme and slowing gastricemptying. The lumen 84 may have a constant, or substantially constant,diameter or the diameter may vary along a length of the lumen 84. Thediameter of the lumen 84 may be smaller than a diameter of the pylorusin at least one region of the lumen 84. For example, the lumen 84 may besmaller than a diameter of the pylorus within the proximal connector 34channel, within the middle connector 42, and/or within the distalconnector 36 channel. The lumen 84 may be narrower than the pylorus inmore than one region and it may be as wide as the pylorus in someregions. In one embodiment, the lumen 84 may be narrowest within thedistal connector 36 channel.

The more resistance to flow that is created, the slower the gastricemptying will be, and more weight loss should occur. Accordingly, thesize of the lumen 84 may be designed or configured based on the level ofobesity in the patient being treated. For morbidly obese patients, thelumen size may be made smaller than for a slightly or moderately obeseperson. Accordingly, the size of the lumen 84 and the aggressiveness ofthe weight loss goal can be tailored to each patient depending on theirsituation and needs. The typical pyloric diameter has been measured tobe from about 7 to 10 mm. In one embodiment, at least a portion of thelumen 84 of the device may be from 3 to 7 mm, or any sub-range therein.For example, the lumen size may be 4 to 6 mm or about 5 mm (e.g., ±0.5mm). The lumen size may be adjusted by changing the channel size of theproximal and/or distal connector 36.

The device may be deployed or inserted into the patient through themouth and into the esophagus and stomach. Since the device is insertedthrough the mouth, the procedure may be performed using endoscopic orradiological guidance. The device may include radiological markers (notshown) to facilitate insertion using fluoroscopy. The procedure may alsobe an outpatient procedure, making it less expensive and less traumaticfor the patient. Insertion and deployment of the device is shown inFIGS. 8-11. In order for the device to be inserted orally into thepatient, it may be manipulated into an insertion or deploymentconfiguration. The device may be placed in the insertion configurationwith the middle connector 42 coupled to the proximal connector 34 butnot to the distal connector 36 (e.g., the distal connector 36 isdetached from the rest of the connector assembly 14 but remains attachedto the strands 16 of the stent 12). While in this state, the distal andproximal connectors may be stretched or pulled axially away from eachother to cause the strands 16 in the first and second portions tostraighten. The distal and proximal connectors may be axially separateduntil the strands 16 in the stent 12 are parallel, or substantiallyparallel, to each other (e.g., aligned along the long axis of thedevice). Once in this insertion configuration, the device may beinserted into a protective sheath 86. The protective sheath 86 mayrestrict the device from returning to its natural or relaxed position(which may have been previously heat formed) prematurely. The sheath 86may also protect the lining of the mouth, esophagus, and stomach duringinsertion of the device.

The device may be manipulated into the insertion configuration using anysuitable manner. For example, the proximal and distal connectors may bepulled apart manually or using a fixture. In one embodiment, a torquecatheter 88 and a balloon catheter 90 may be used to move the deviceinto the insertion configuration. The torque catheter 88 may be acatheter having a high torque capability, such that it is able to applytorque at its end or tip. For example, the torque catheter 88 mayinclude braiding of fabric or metal to increase its ability to applytorque before the catheter twists or distorts. The end or tip of thetorque catheter 88 may have an engagement portion 92, such as afastener, attached thereto. The engagement portion 92 may be integrallyformed with the torque catheter 88 (e.g., as a single component), or itmay be attached using adhesive, a fastener, or other known methods. Inat least one embodiment, the engagement portion 92 may include afastener having threading that is configured to engage the threadedportion 76 of the distal connector 36. The fastener may have malethreading to engage with female threading in the threaded portion, orvice versa. While the fastener may engage the distal connector 36 usingthreading, other methods of releasable attachment may be used. Thetorque catheter 88 may also be referred to as a torque tube or a torquecable, and may have a lumen or passage extending therethrough. Thetorque tube may therefore be passed over the guide wire 94 and throughthe lumen in the proximal connector 34 and the lumen in the middleconnector 42 to engage and releasably couple to the distal connector 36.

The balloon catheter 90 may also have a lumen or passage extendingtherethrough, and the lumen may be sized to be passed over both theguide wire 94 and the torque catheter 88. The balloon catheter 90 may beinserted with the balloon in a deflated state and inflated within thepatient, as is known in the art. To move the device into the insertionconfiguration, the fastener of the torque tube 88 may be engaged andcoupled to the distal connector 36, such as by engaging the threads ofthe threaded portion 76. The balloon catheter 90 may be inserted atleast partially into the proximal connector 34, for example, at leastpartially into the lumen, in a deflated state and then inflated suchthat it is secured by friction within the proximal connector 34. To movethe device to the insertion configuration, tension may be applied to thedistal connector 36 by the torque tube 88 and the proximal connector 34may be pulled axially away from the distal connector 36 using theballoon catheter 90. Once in the insertion configuration (e.g., strands16 parallel in axial direction), the device may be inserted into theprotective sheath.

In one embodiment, the device 10 (e.g., within a protective sheath) maybe inserted over a guide wire 94, for example, a standard 0.035 inch or0.038 inch guide wire. The guide wire 94 may be inserted into the mouthof the sedated patient, through the esophagus and stomach, and into theduodenum. The device, optionally enclosed in a protective sheath, maythen be inserted into the patient over the guide wire 94 (e.g., byinserting the other end of the guide wire 94 through the lumen of theconnector assembly 14). The device may be inserted with the torque tube88 engaged with the distal connector 36, such as through a threadedengagement between the fastener and the threaded portion 76. Thephysician may use a contrast agent, such as barium sulfate solution, ordirect endoscopy to locate the pylorus and pyloric sphincter. Thephysician may position the device within the pylorus while the device isin the insertion configuration and, optionally, within a protectivesheath.

The device may be positioned such that when the device is in thedeployed configuration, the first portion 18 is proximal to the pylorusand the second portion 20 is distal to the pylorus. When the device ispositioned correctly, the protective sheath may be removed (if present).Removal of the sheath may allow the device to return to its natural orrelaxed configuration having the first and second portions with enlargeddiameters (e.g., “humps”). To lock or secure the device into thedeployed configuration, the distal and proximal connectors may be movedor pulled axially towards each other. The device may be locked bypushing or applying a forward axial force (e.g. in a direction from theproximal connector 34 towards the distal connector 36) on the proximalconnector 34 using the balloon catheter 90 while applying a pulling orapplying a rearward axial force on the distal connector 36 using thetorque tube 88. The forces applied may cause the proximal connector 34to stay relatively stationary while the distal connector 36 movestowards the proximal connector 34 (e.g., force is applied to the ballooncatheter 90 to hold the proximal connector 34 in place) or vice versa(e.g., force is applied to the torque tube 88 to hold the distalconnector 36 in place and the balloon catheter 90 is pushed towards thedistal connector 36). The forces may also be applied such that both theproximal and distal connectors move towards each other.

In the insertion configuration, the middle connector 42 may be coupledto the proximal connector 34, for example, by a threaded connection(described above). Accordingly, when the proximal and distal connectorsmove towards each other, the middle connector 42 may engage and coupleto the distal connector 36 to lock the connector assembly 14 together.When the middle connector 42 is pulled toward the distal connector 36,the projections 58 of the middle connector 42 may engage the flange orlip 74 of the distal connector 36 and flex or deflect. The deflectionmay be facilitated by the ramp(s) on the snap fit element(s) 66 of theprojection(s) 58, which may provide an angled surface that causes theprojections to deflect inward towards a longitudinal axis or center lineof the middle connector 42. As the middle connector 42 continues to movetoward the distal connector 36, the ramp(s) of the snap fit elements 66may extend beyond or passed the flange 74 of the distal connector 36 andthe projections may flex or deflect back to their original position, orclose thereto (e.g., the projections may still be flexed slightlyinward). Once the snap fit elements 66 extend distally beyond the flange74 of the distal connector 36, the stops of the snap fit elements mayengage the flange and prevent the middle connector 42 from movingrearward or proximally from the distal connector 36 (or the distalconnector 36 from moving forward or distal from the middle connector42). The projections and snap fit elements may be sized such that thedistal tips of the snap fit elements contact or nearly contact a portionof the distal connector 36 distal to the flange. This may preventadditional relative movement between the middle and distal connectors inthe opposite direction (e.g., towards each other) once they are engagedand locked.

Engaging and locking the connector assembly 14 together may move thestent 12 from its relaxed position into the deployed configuration.Since the first and second ends of the strands 16 may be connected tothe proximal and distal connectors, respectively, bringing the proximaland distal connectors together may move the strands 16 from a relativelygentle or mild hump into a more steep disc or “pancake” shape. Thelocked stent 12 may form the first and second portions, with the sizesand dimensions described above.

Once the device is locked into the deployed configuration, the ballooncatheter 90 and the torque catheter 88 may be removed. The ballooncatheter 90 may first be deflated. Then, the fastener of the torquecatheter 88 may be decoupled from the distal connector 36, for example,by unscrewing from the threaded portion, and withdrawn over the guidewire 94. However, the order of removal may also be reversed (e.g.,torque tube removed first, then balloon catheter 90).

During insertion, the duodenal (or duodenal-jejunal) sleeve may be in acompact, condensed, or rolled-up configuration. In one embodiment, thesleeve may be attached to the device (e.g., to the distal connector 36)which is enclosed in the protective sheath. The sleeve may be formed ofa very thin walled polymer (e.g., less than 25 microns wall thickness)which may be inserted between the protective sheath and the device(e.g., the stent 12). The sheath may be rolled, folded, crumpled, orloose when inserted. To prevent the sheath from emerging from theprotective sheath prematurely, the duodenal sleeve may include a loop ofmaterial, such as a suture, which restrains the duodenal sleeve. Arelease mechanism, such as a slip knot, in the material may allow theimplanting physician to release the sheath by pulling on the releasemechanism. When the protective sheath is ready for removal, the stent 12may be across the pyloric sphincter and the sleeve may be downstream inthe duodenum and proximal jejunum. The protective sheath covering thestent 12 and sleeve may be removed by pulling the protective sheath in aretrograde direction axially towards the mouth while applying a fixedforce to the balloon catheter 90 and torque tube. The sleeve may bereleased into the duodenum and the stent 12 can be positioned tostraddle the pyloric sphincter.

In another embodiment, the sleeve may be rolled up or folded. Similar toabove, the rolled up sleeve may be deployed downstream into the duodenumand jejunum. In one embodiment, the sleeve may be deployed by applyingfluid pressure to the sleeve. A balloon catheter 90 having anelastomeric seal (e.g., a Touhy-borst connector) may seal the guide wire94 while allowing fluid such as saline or water to be pushed down thelumen of the catheter around the guide wire 94. Once the device islocked into the deployed configuration, the sleeve may be released andallowed to move or “float” into and down the duodenum and proximaljejunum (depending on length). The sleeve may be pushed down theduodenum by natural forces (e.g., without further action by thephysician), such as the flow of partially digested food. Alternatively,the sleeve may be pushed or assisted down the duodenum by the physician.In one embodiment, a balloon catheter, which may be the same ordifferent from the balloon catheter used to position and lock thedevice) may be inflated and extended over the guide wire 94 to push thesleeve into and down the duodenum (and proximal jejunum, depending onlength). If the balloon catheter is the same one used for positioningand locking the device, it may be used to deploy the sleeve prior tobeing withdrawn or it may be re-inserted after being withdrawn.

The device may be removed after insertion in a simple out-patientprocedure, similar to insertion. The device may be removed when thepatient has lost a certain amount of weight, or for any other reason. Asdescribed above, when the device is in the deployed configuration, theconnector assembly 14 may be locked such that the distal, middle, andproximal connectors cannot separate and the stent 12 maintains the firstand second portions having enlarged diameters. In order to remove thedevice, the connector assembly 14 may be unlocked such that the stent 12may be collapsed or condensed into a retrieval configuration. Theretrieval configuration may be similar to the insertion configuration,in that the strands 16 of the stent 12 may be parallel or substantiallyparallel and aligned along the longitudinal axis of the device. Tounlock the device, the proximal connector 34 may be decoupled from themiddle connector 42 (which may be locked to the distal connector 36 bysnap fit elements). Since the strands 16 of the stent 12 may beunattached to the middle connector 42, the middle connector 42 may bedisconnected from either of the proximal or distal connectors in orderto unlock the device.

In one embodiment, described above, the middle connector 42 and theproximal connector 34 may be coupled by a threaded engagement. In thisembodiment, a release mechanism 50 may be provided to control thedisengagement of the middle and proximal connectors. The releasemechanism 50 may be configured to prevent relative movement of theconnectors until the release mechanism 50 is activated or actuated. Asdescribed above, the release mechanism 50 may include a pin or rod 52,which may be inserted into a passage formed in the middle and proximalconnectors. The pin 52 may prevent the threads of the proximal andmiddle connectors from unscrewing when the pin 52 is inserted. The pitchof the threads may be configured to allow the proximal and middleconnectors to be unscrewed with relatively little force being appliedwhen the pin 52 is not inserted.

The release mechanism 50 may also include a hook or curved/bent portion96. The hook 96 may extend from the pin 52 and may be configured to besnared. The release mechanism 50 may be tethered or attached to thedevice, for example, to the proximal connector 34. The release mechanism50 may be tethered at the pin, the hook 96, or another location. Theattachment to the device may be flexible or rigid. In one embodiment,the tether 98 is a flexible polymer thread or a suture. The attachmentof the tether to the release mechanism 50 and/or device may be byadhesive, welding (e.g., ultrasonic), by mechanical fastening, knotting,or any other suitable method. In one embodiment, the hook 96 may beformed from tubing (e.g., hypodermic tubing) and the hooked tubing maybe swaged the around a high strength chord material. For example, Kevlartwine may be used as a tether and may be swaged to the hook. The tethermay be attached to the proximal connector 34 by tying the tether 98directly to the connector. The proximal connector 34 may include severalholes 100 (e.g., molded in) through which the tether is threaded andtied.

To unlock the connector assembly 14, a snare (not shown) may be insertedinto the mouth and through the esophagus and stomach. The snare may beany device configured to engage and actuate the release mechanism 50. Ifthe release mechanism 50 includes a hook 96, the snare may include aloop or a hook to engage the hook 96. The snare may be inserted byitself or through/over a catheter or guide wire 94 or within asleeve/sheath. A physician may use an endoscope or radiology (e.g.,fluoroscopy), or any other suitable approach, to guide the snare.

When the device is to be removed, the physician may use the snare toengage and actuate the release mechanism 50. This may include looping asnare over a hook 96 of the release mechanism 50 and pulling on the hook96 to remove the pin 52 from the passage 56 (or at least remove it fromblocking the threads of the connectors). Once the pin 52 is removed, thethreads of the middle and proximal connectors may no longer be lockedand prevented from unscrewing. As described above, the threads may beconfigured to unscrew relatively easily (e.g., large pitch and angle ofrepose). To facilitate the unscrewing of the threads, the physician maycontinue pulling on the hook 96, which may be tethered to the proximalconnector 34. The axial pulling force may cause the threads to unscrew,thereby uncoupling the middle and proximal connectors. Since the stent12 may only be attached to the distal and proximal connectors, continuedpulling on the hook 96 using the snare may cause the strands 16 of thestent 12 to straighten out. The stent 12 may be pulled until the strands16 are parallel or substantially parallel to each other, which may bereferred to as the retrieval configuration. The retrieval configurationmay be similar to the insertion configuration, except that the proximalconnector 34 is free and the middle and distal connectors are coupled inthe retrieval configuration.

The stent 12 may be pulled into a protective sheath (e.g., similar tothe sheath used for insertion) by pulling on the snare and hook 96 untilthe stent 12 is fully collapsed inside the protective sheath. Once thestent 12 is pulled into the retrieval configuration within theprotective sheath, the device and sheath may be removed through thepatient's mouth, for example, by continued pulling on the releasemechanism 50 using the snare (e.g., a loop over a tethered hook 96) orby pulling on the sheath. Since the duodenal sheath may be fixed to thedevice, it may also be removed through the mouth. The protective sheathmay prevent trauma to the stomach, esophagus, and mouth during removal.

Alternatively, the device may be removed without the protective sheath.In this embodiment, a counter axial force may be applied to the deviceto stretch the strands 16 and cause the strands 16 to straighten intothe retrieval configuration. To remove the device without a protectivesheath, a guide wire 94 may be threaded through unlocked stent 12 toallow a torque catheter 88 to travel over the wire and engage with thedistal connector 36. Once the torque tube with the threaded distal endengages the female threads on the distal connector 36, the torque tubecan be screwed to the distal connector 36. A balloon catheter 90 may beslid over the torque tube/guidewire and the balloon may be inflated tofrictionally engage the proximal connector 34. By pushing on the torquetube while axially pulling the balloon catheter 90, the stent 12 can bestretched such that the strands 16 straighten. The stretched stent 12can be removed by pulling both the torque tube and balloon catheter 90from the patient's mouth. The attached duodenal sleeve will follow thestent 12 and emerge through the patient's esophagus and mouth.

The disclosed device and methods allow for a simple procedure performedthrough a natural orifice (mouth) without any incisions or stapling. Asa result, the device may dramatically reduce the complication ratecompared to other approaches. Such an effective non-surgical alternativeweight loss procedure may significantly decrease the rising burden ofhealth care costs in the US and around the globe. The procedure isreversible, technically easy, does not require hospitalization, is costeffective relative to surgery, and produces effective long term weightloss. The device may inhibit weight loss and reduce type 2 diabetes. Thedevice may be used to treat patients who are not morbidly obese so thatthe treatment of type 2 diabetes can be introduced earlier in theprogression of the disease, since researchers have shown that treatingless advanced cases of diabetes via surgical techniques have much lowerlikelihood to re-develop the disease. The device may provide a dualsolution for weight loss; a restricted pyloric canal to slow foodpassage and a duodenal-jejunal sleeve to prevent absorption of nutrientsin the small intestines. The device uses a benign anchor locking andunlocking system which does not rely on barbs or hooks to retain thestent nor the duodenal sleeve in place. The stent may be encapsulated ina sheath to prevent tissue in growth and ease removal. The device can beeasily implanted and explanted by physicians from multiple specialtiesthrough the natural orifice of the mouth.

While exemplary embodiments are described above, it is not intended thatthese embodiments describe all possible forms of the invention. Rather,the words used in the specification are words of description rather thanlimitation, and it is understood that various changes may be madewithout departing from the spirit and scope of the invention.Additionally, the features of various implementing embodiments may becombined to form further embodiments of the invention.

What is claimed is:
 1. A gastrointestinal device for reducing flow through a pyloric sphincter of a patient, comprising: a stent including a plurality of strands forming first and seconds ends, the plurality of strands configured to move between a retrieval configuration, wherein the plurality of strands are substantially parallel, and a deployed configuration, wherein the plurality of strands form a proximal portion having a first diameter and a distal portion having a second diameter, the first and second diameters being larger than a diameter of the pyloric sphincter; a connector assembly including a proximal connector, a middle connector, and a distal connector, the middle connector coupled to the proximal connector and the distal connector when the plurality of strands are in the deployed configuration and the plurality of strands being attached at the first end to the proximal connector and at the second end to the distal connector; a release mechanism attached to the proximal connector and configured to decouple the proximal connector from the middle connector, wherein decoupling of the proximal and middle connectors allows the plurality of strands to move from the deployed configuration to the retrieval configuration. 